MBX Extreme PCC magazine extensions add capacity to competition carbine magazines, pushing round count beyond factory limits for USPSA PCC stages that demand sustained fire strings. Extension sleeves, base plates, and spring kits are precision-fit for MBX PCC magazines, ensuring reliable feeding under the full column weight of extended loads. Anodized aluminum construction holds up under repeated stage drops and rough stage terrain. Fast same-day shipping on most orders at Shooters Connection.